Investigation of CO ₂ laser treated concrete in terms of water absorption through dissimilar layers

A comprehensive investigation of the effectiveness of a CO ₂ laser generated glaze on the absorption characteristics of OPC has been conducted. The experimental results from the absorption tests confirmed that the CO ₂ laser generated glaze surface on the OPC had successfully reduced the absorption rate by 77% as compared to the untreated OPC. The presence of dissimilar layers on both the untreated and CO ₂ laser treated OPC was established. Two dissimilar layers, which were the OPC material and the concrete material respectively were identified for the untreated concrete. As for the CO: laser treated OPC, four dissimilar layers were identified. These were the glaze, the HAZ, the OPC and the concrete aggregate respectively. For the CO ₂ laser treated OPC, the sorptivity of the first layer (CO ₂ laser generated glaze) was 0 mm min ^-1/2 on account of the fact that it is an amorphous structure. The sorptivity of the second layer (HAZ) was 0.057 mm min ^-1/2, which was 42.5% higher than the third layer (OPC) where the sorptivity value was 0.040 mm min ^-1/2. Consequently, it was concluded that reduction in the thickness of the HAZ layer and improvement in the quality of glaze layer would further enhance the effectiveness of the CO ₂ generated glaze on the OPC surface of the concrete.